A rapid and quantitative post-wildfire damage assessment of buildings in the 2025 Palisades fire in California based on InSAR

Abstract

Timely identification of post-wildfire damage information is critical for protecting communities and infrastructure. Yet extreme thermal conditions and limited ground accessibility often constrain the effectiveness of traditional assessment methods. This study presents a novel approach for inferring post-wildfire building damage based on Interferometric Synthetic Aperture Radar (InSAR). Instead of directly observing structural damage, we use InSAR to capture vertical surface deformations induced by thermal disturbances during the 2025 Palisades Fire in Los Angeles County, California. The deformation patterns under intense wildfire, such as thermal expansion during heating and subsidence caused by thermal contraction after cooling, as well as soil moisture loss, etc., can be extracted by comparing pre- and post-fire SAR images, and then spatially correlated with building footprints and optical imagery to infer damage intensity. The case study results show that this InSAR-based approach effectively identifies zones of probable structural damage according to deformation intensity, providing a cost-efficient, physics-based supplement to existing post-wildfire damage assessment techniques.